Laser drilling is a technique for forming holes in various materials, including hard to process materials such as aircraft grade castings. Laser drilling can be used to form very small holes, including holes that are created at an angle that may be otherwise very difficult to form.
Holes formed by laser drilling and other processes may be used to conduct gasses. For example, a turbine engine's turbine blades may have a series of holes through which cooling air may pass to form a cooled boundary layer around the blade. The flow of gasses through these holes can be a functional aspect of the blade that is difficult to measure.